1. Field of the Invention
The present invention relates particularly to a nitride semiconductor represented by BpAlqGarInsN (0xe2x89xa6pxe2x89xa61, 0xe2x89xa6qxe2x89xa61, 0xe2x89xa6rxe2x89xa61, 0xe2x89xa6sxe2x89xa61, p+q+r+s=1), a nitride semiconductor luminescence device, a method for producing a nitride semiconductor, and a method for producing a semiconductor luminescence device.
2. Description of the Related Art
As a conventional method for obtaining a p-type semiconductor of a gallium nitride based compound, there is generally known a method of using a magnesium organic metal as a raw material of a p-type dopant.
It is know that magnesium, Mg, makes it possible to produce the sallowest acceptor level among p-type impurities that have been known up to now.
However, in the case that hydrogen is contained in a carrier gas for raw materials in gaseous growth, a phenomenon occurs that an acceptor of Mg becomes inactive in gallium nitride based crystal. By annealing the film of this inactive gallium nitride at about 700-900xc2x0 C. in an inert gas, the carrier concentration can be measured, and it is known that the resultant becomes a p-type (S. Nakamura et al., Japan Journal of Applied Physics, 30, (10A) L1708-L1711 (1991)).
The level of Mg impurity is so deep as about 200 meV. Thus, even if all of the Mg atoms become acceptors, the carrier concentration at room temperature becomes lower by about 2 figures than it.
As described above, in gallium nitride based compound semiconductors, in particular, p-type gallium nitride based compound semiconductors, the carrier concentration at room temperature comes into question. In order to improve the concentration of the carriers at room temperature, the impurity level thereof needs to be sallow.
The present invention has been made to solve this problem.
According to the present invention, there is provided a nitride semiconductor of p-type BpAlqGarInsN (0xe2x89xa6pxe2x89xa61, 0xe2x89xa6qxe2x89xa61, 0xe2x89xa6rxe2x89xa61, 0xe2x89xa6sxe2x89xa61, p+q+r+s=1), having a point defect concentration of 1xc3x971019 cmxe2x88x923 or more, thereby making it possible to obtain a high carrier concentration.
According to the present invention, there is provided a nitride semiconductor luminescence device comprising nitride semiconductor layers made of p-type BpAlqGarInsN (0xe2x89xa6pxe2x89xa61, 0xe2x89xa6qxe2x89xa61, 0xe2x89xa6rxe2x89xa61, 0xe2x89xa6sxe2x89xa61, p+q+r+s=1), wherein at least one of the p-type nitride semiconductor layers has a point defect concentration of 1xc3x971019 cmxe2x88x923 or more, thereby making it possible to obtain a high carrier concentration.
According to the present invention, there is provided a method for producing a p-type nitride semiconductor of BpAlqGarInsN (0xe2x89xa6pxe2x89xa61, 0xe2x89xa6qxe2x89xa61, 0xe2x89xa6rxe2x89xa61, 0xe2x89xa6sxe2x89xa61, p+q+r+s=1), wherein the p-type nitride semiconductor having a point defect concentration of 1xc3x971019 cmxe2x88x923 or more is grown.
According to the present invention, there is provided a method for producing a p-type nitride semiconductor of BpAlqGarInsN (0xe2x89xa6pxe2x89xa61, 0xe2x89xa6qxe2x89xa61, 0xe2x89xa6rxe2x89xa61, 0xe2x89xa6sxe2x89xa61, p+q+r+s=1), wherein the supplying ratio V/III of a V group raw material to a III group raw material is set to 1000-5000 to grow the p-type nitride semiconductor.
According to the present invention, there is a provided method for producing a p-type nitride semiconductor of BpAlqGarInsN (0xe2x89xa6pxe2x89xa61, 0xe2x89xa6qxe2x89xa61, 0xe2x89xa6rxe2x89xa61, 0xe2x89xa6sxe2x89xa61, p+q+r+s=1), wherein the p-type nitride semiconductor is grown at a growing rate of 4 xcexcm/hour or more.
The method for producing a nitride semiconductor of the present invention can be based on any combination of the above-mentioned various methods for producing the nitride semiconductor.
According to the present invention, there is provided a method for producing a nitride semiconductor luminescence device comprising p-type nitride semiconductor layers made of BpAlqGarInsN (0xe2x89xa6pxe2x89xa61, 0xe2x89xa6qxe2x89xa61, 0xe2x89xa6rxe2x89xa61, 0xe2x89xa6sxe2x89xa61, p+q+r+s=1), wherein at least one of the p-type nitride semiconductor layers is grown as a p-type nitride semiconductor having a point defect concentration of 1xc3x971019 cmxe2x88x923 or more.
According to the present invention, there is provided a method for producing a nitride semiconductor luminescence device comprising p-type nitride semiconductor layers made of BpAlqGarInsN (0xe2x89xa6pxe2x89xa61, 0xe2x89xa6qxe2x89xa61, 0xe2x89xa6rxe2x89xa61, 0xe2x89xa6sxe2x89xa61, p+q+r+s=1), wherein at least one of the p-type nitride semiconductor layers is grown in the manner that the supplying ratio V/III of a V group raw material to a III group raw material is set to 1000-5000.
According to the present invention, there is provided a method for producing a nitride semiconductor luminescence device comprising p-type nitride semiconductor layers made of BpAlqGarInsN (0xe2x89xa6pxe2x89xa61, 0xe2x89xa6qxe2x89xa61, 0xe2x89xa6rxe2x89xa61, 0xe2x89xa6sxe2x89xa61, p+q+r+s=1), wherein at least one of the p-type nitride semiconductors is grown at a growing rate of 4 xcexcm/hour or more.
The method for producing a nitride semiconductor luminescence device of the present invention can be based on any combination of the above-mentioned various methods for producing the nitride semiconductor luminescence device.
It has been proved that in the above-mentioned nitride semiconductor or the above-mentioned nitride semiconductor luminescence device of the present invention, the p-type BpAlqGarInsN (0xe2x89xa6pxe2x89xa61, 0xe2x89xa6qxe2x89xa61, 0xe2x89xa6rxe2x89xa61, 0xe2x89xa6sxe2x89xa61, p+q+r+s=1) has a high carrier concentration at room temperature. This is based on the fact that the acceptor level of dopant Mg becomes shallow or a new shallow level is generated. This fact has been made clear by temperature variable hole measurement.